Salud sexual y reproductiva en estudiantes universitarios de una institución de educación superior en Colombia / Sexual and reproductive health in university students at an institution of higher learning in Colombia

Objetivo Investigar en una universidad estatal del Caribe colombianoel estado de la salud sexual y reproductiva especialmente conocimientos sobre Enfermedades de Transmisión Sexual (ETS), fertilidad, sexualidad, embarazo y violencia. Métodos Estudio transversal tipo encuesta. Se seleccionaron estudiantes matriculados en el segundo período de 2010 que llenaron voluntariamente la encuesta. Los datos cualitativos fueron tabulados y graficados usando medidas de tendencia central para variables cuantitativas. Resultados La población tenía alrededor de 20 años de edad, provenía de la zona urbana (57,9%; IC95%=54,7-61,1), predominantemente heterosexual (89,7%) con edad de inicio de vida sexual antes de los 18 años, con 11,8 % de promiscuidad que usaba principalmente el preservativo como Método de Planificación Familiar (MPF) (55 %). Aunque poseían información previa sobre salud sexual, MPF y ETS, no se comportaban acorde con ello, por la desinformación sobre formas de transmisión del VIH, bajo nivel de realización de pruebas serológicas para ETS, así como conductas de riesgo (sexo/alcohol/drogas). El 12,3% tuvo antecedente de embarazo, violencia física (21,6%) y sexual (4,6%) con un predominante silencio de las víctimas de abuso sexual (61,8%). Conclusiones La muestra refleja la población universitaria de esta región del país. Se planea organizar un programa con apoyo médico y psicológico que permita disminuir los índices de ETS, embarazos no planificados, preparando al adolescente en esta importante etapa de su vida, sirviendo de modelo para otras universidades latinoamericanas.

Objective To investigate the state of sexual and reproductive health in students at a public university in the Colombian Caribbean, with an emphasis on sexually transmitted diseases (STDs), fertility, sexuality, pregnancy and violence. Methods Cross-sectional survey study. University students, enrolled in the second semester of 2010 and who completed a self-administered survey based on the Reproductive Health survey of the Pan American Health Organization, were selected. Qualitative data was tabulated and graphed using measures of central tendency for quantitative variables. Results The age of population studied was around 20 years old, came from the urban area (57.9 %; IC95 %=54.7-61.1), was predominantly heterosexual (89.7 %), with an age of initiation of sexual activity of less than 18 years old, 11.8 % promiscuity, mainly using the condom as a Family Planning Method (FPM) (55 %). Although they had prior information on sexual health, STDs and FPMs, they did not behave according to this due to low education about HIV transmission routes, low incidence of serological tests for STDs, and high risk behavior (sex/alcohol/drugs). It was observed that 12.3 % had a history of pregnancy, physical violence (21.6 %) and sexual violence (4.6 %) with a predominant silence from the victims of sexual abuse (61.8 %). Conclusion The sample reflects the student population in this region of Colombia. We plan to organize a health program with medical and psychological support to reduce the rates of STDs and unplanned pregnancies, preparing the adolescent for this important step in their life and serving as a model for other Latin American universities.

[Sexual and reproductive health in university students at an institution of higher learning in Colombia]. / Salud sexual y reproductiva en estudiantes universitarios de una institución de educación superior en Colombia.

OBJECTIVE: To investigate the state of sexual and reproductive health in students at a public university in the Colombian Caribbean, with an emphasis on sexually transmitted diseases (STDs), fertility, sexuality, pregnancy and violence. METHODS: Cross-sectional survey study. University students, enrolled in the second semester of 2010 and who completed a self-administered survey based on the Reproductive Health survey of the Pan American Health Organization, were selected. Qualitative data was tabulated and graphed using measures of central tendency for quantitative variables. RESULTS: The age of population studied was around 20 years old, came from the urban area (57.9 %; IC95 %=54.7-61.1), was predominantly heterosexual (89.7 %), with an age of initiation of sexual activity of less than 18 years old, 11.8 % promiscuity, mainly using the condom as a Family Planning Method (FPM) (55 %). Although they had prior information on sexual health, STDs and FPMs, they did not behave according to this due to low education about HIV transmission routes, low incidence of serological tests for STDs, and high risk behavior (sex/alcohol/drugs). It was observed that 12.3 % had a history of pregnancy, physical violence (21.6 %) and sexual violence (4.6 %) with a predominant silence from the victims of sexual abuse (61.8 %). CONCLUSION: The sample reflects the student population in this region of Colombia. We plan to organize a health program with medical and psychological support to reduce the rates of STDs and unplanned pregnancies, preparing the adolescent for this important step in their life and serving as a model for other Latin American universities.

Development of a versatile biotinylated material based on SU-8.

The negative epoxy-based SU-8 photoresist has a wide variety of applications within the semiconductor industry, photonics and lab-on-a-chip devices, and it is emerging as an alternative to silicon-based devices for sensing purposes. In the present work, biotinylation of the SU-8 polymer surface promoted by light is reported. As a result, a novel, effective, and low-cost material, focusing on the immobilization of bioreceptors and consequent biosensing, is developed. This material allows the spatial discrimination depending on the irradiation of desired areas. The most salient feature is that the photobiotin may be directly incorporated into the SU-8 curing process, consequently reducing time and cost. The potential use of this substrate is demonstrated by the immunoanalytical detection of the synthetic steroid gestrinone, showing excellent performances. Moreover, the naked eye biodetection due to the transparent SU-8 substrate, and simple instrumental quantification are additional advantages.

Biomolecular Interaction Analysis of Gestrinone-anti-Gestrinone Using Arrays of High Aspect Ratio SU-8 Nanopillars.

In this paper, label-free biosensing for antibody screening by periodic lattices of high-aspect ratio SU-8 nano-pillars (BICELLs) is presented. As a demonstration, the determination of anti-gestrinone antibodies from whole rabbit serum is carried out, and for the first time, the dissociation constant (KD = 6 nM) of antigen-antibody recognition process is calculated using this sensing system. After gestrinone antigen immobilization on the BICELLs, the immunorecognition was performed. The cells were interrogated vertically by using micron spot size Fourier transform visible and IR spectrometry (FT-VIS-IR), and the dip wavenumber shift was monitored. The biosensing assay exhibited good reproducibility and sensitivity (LOD = 0.75 ng/mL).

On-chip temperature compensation in an integrated slot-waveguide ring resonator refractive index sensor array.

We present an experimental study of an integrated slot-waveguide refractive index sensor array fabricated in silicon nitride on silica. We study the temperature dependence of the slot-waveguide ring resonator sensors and find that they show a low temperature dependence of -16.6 pm/K, while at the same time a large refractive index sensitivity of 240 nm per refractive index unit. Furthermore, by using on-chip temperature referencing, a differential temperature sensitivity of only 0.3 pm/K is obtained, without individual sensor calibration. This low value indicates good sensor-to-sensor repeatability, thus enabling use in highly parallel chemical assays. We demonstrate refractive index measurements during temperature drift and show a detection limit of 8.8 x 10-6 refractive index units in a 7 K temperature operating window, without external temperature control. Finally, we suggest the possibility of athermal slot-waveguide sensor design.

Selective chemical modification of silicon nitride/silicon oxide nanostructures to develop label-free biosensors.

The selective introduction of functional groups on the surface of silicon nitride/silicon oxide nanostructures was studied. Chemical strategies based on organosilane, Si-H and N-H reactivities were assayed. Among these strategies, the use of glutaraldehyde to selectively immobilize biomolecules only on the silicon nitride part of the chip surface was the most effective for the covalent attachment of proteins, maintaining also their bioavailability. The biomolecule surface coverage results up to 80% and the modification is selective versus silicon oxide; the biomolecule attaching only to silicon nitride and leaving the silicon oxide area of the device unmodified. The effectiveness of our novel selective surface modification procedure is also supported by comparing experimental and numerical calculations of the optical performance of a label-free optical ring resonator based on Si(3)N(4)/SiO(2) slot-waveguides.

Label-free optical biosensing with slot-waveguides.

We demonstrate label-free molecule detection by using an integrated biosensor based on a Si(3)N(4)/SiO(2) slot-waveguide microring resonator. Bovine serum albumin (BSA) and anti-BSA molecular binding events on the sensor surface are monitored through the measurement of resonant wavelength shifts with varying biomolecule concentrations. The biosensor exhibited sensitivities of 1.8 and 3.2 nm/(ng/mm(2)) for the detection of anti-BSA and BSA, respectively. The estimated detection limits are 28 and 16 pg/mm(2) for anti-BSA and BSA, respectively, limited by wavelength resolution.

Slot-waveguide biochemical sensor.

We report an experimental demonstration of an integrated biochemical sensor based on a slot-waveguide microring resonator. The microresonator is fabricated on a Si3N4-SiO2 platform and operates at a wavelength of 1.3 microm. The transmission spectrum of the sensor is measured with different ambient refractive indices ranging from n=1.33 to 1.42. A linear shift of the resonant wavelength with increasing ambient refractive index of 212 nm/refractive index units (RIU) is observed. The sensor detects a minimal refractive index variation of 2x10(-4) RIU.

Assessment of antifouling effectiveness of two natural product antifoulants by attachment study with freshwater bacteria.

UNLABELLED: GOAL, SCOPE, BACKGROUND: The traditional solution for keeping unwanted organisms from attaching to submerged surfaces is to apply anti-fouling coatings. The most common antifoulant was tributyltin (TBT). TBT systems were highly effective but were also toxic to non-target organisms. The use of the TBT based coatings will be completely banned by January 1, 2008. Therefore, there is an urgent need to seek out suitable non-toxic alternatives. METHODS: The aim of this work was to evaluate the effectiveness of capsaicin and zosteric acid as natural product antifoulants (NPAs) in deterring bacterial attachment. Two fresh water bacteria systems Pseudomonas putida (Pp) and bacteria isolated from Lake Erie (LE) were used to assess the attachment when the NPAs dispersed in the water. Effectiveness was ascertained based on the decrease in microbial attachment, limited toxicity, and minimum alteration of the coatings properties. RESULTS AND DISCUSSION: A significant inhibition of bacteria attachment was achieved when aqueous capsaicin concentration was increased from 0 to 40 mg/L. For instance, after 14 days the LE system depicted 93.5% and 98.5% less biofilm coverage for 20 mg/L and 40 mg/L capsaicin, respectively when pared to systems without NPA. Biofilm coverage was reduced by 92.5% and 98.2%, respectively with 50 mg/L and 500 mg/L zosteric acid. CONCLUSIONS: Both capsaicin and zosteric acid was effective at preventing bacteria attachment. As the NPA aqueous concentration increased, biofilm formation decreased. Evaluating changes in aqueous pH, conductivity, dissolved oxygen, aqueous microbial population and biofilm formation suggested that the primary antifoulant mechanism of these two NPAs was to block the bacteria's active sites versus posing a lethal level. RECOMMENDATION AND PERSPECTIVE: From the attachment study, zosteric acid appeared to be more effective in preventing bacterial attachment when the NPAs were dispersed in the aqueous environment. For practical applications, the antifoulant needs to be incorporated into a coating and have a slow release rate. Thus the ability to successfully incorporate zosteric acid into a coating, without deterring bacterial attachment, needs to be investigated.

Evaluation of toxicity of capsaicin and zosteric acid and their potential application as antifoulants.

The toxicity of two natural product antifoulants, capsaicin and zosteric acid, was evaluated using the Microtox assay and a static toxicity test. The EC50 values obtained from the Microtox assay for capsaicin and zosteric acid were 11.75 +/- 1.02 and 442 +/- 100 mg/L, respectively. The static toxicity test, conducted with freshwater organisms, yielded capsaicin EC50 values of 5.5 +/- 0.5 and 23 +/- 2.0 mg/L for P. putida and Lake Erie bacteria, respectively. Zosteric acid EC50 values were 167 +/- 3.9 and 375 +/- 10 mg/L for P. putida and Lake Erie bacteria, respectively. Tests with marine organisms resulted in capsaicin EC50 values of 6.9 +/- 0.2 and 15.6 +/- 0.4 mg/L for V. natriegens and V. parahaemolyticus, respectively; whereas zosteric acid EC50 values were 7.4 +/- 0.1 and 18 +/- 0.6 mg/L for V. natriegens and V. parahaemolyticus, respectively. These results indicate that zosteric acid is much less toxic than capsaicin and that both are substantially less toxic than the currently used antifoulants, such as TBT (EC50 < 0.01 ppb). Their effectiveness as natural antifoulants was demonstrated by preliminary attachments studies. As the aqueous antifoulant concentration increased, significant inhibition of bacteria attachment or prevention of biofilm formation was achieved. Hence, both capsaicin and zosteric acid could be attractive alternatives as new antifouling compounds.

Incorporating zosteric acid into silicone coatings to achieve its slow release while reducing fresh water bacterial attachment.

Biofouling has posed serious problems in maritime industry including increased fuel consumptions, economic loss from ship-hull maintenances, contamination of drinking water, and serious corrosion for mechanical instruments. Minimizing the attachment of bacteria and formation of biofilm could be advantageous in reducing the early stages of biofouling. Zosteric acid, a natural product present in eelgrass, was found to have ability for preventing the attachment of some bacteria and barnacles. In this study, the antifouling ability of zosteric acid during the early stages of fouling was evaluated using attachment studies of fresh water bacteria. Simultaneously, various methods were sought for incorporating zosteric acid into silicone to prolong the release of the compound. The main results from this study were that zosteric acid exhibited anti-bacterial attachment regardless of whether it dispersed in water or incorporated into a coating. In addition, the release rate of zosteric acid from the incorporated coatings, particularly those where zosteric acid was uniformly dispersed with aggregates size of 4 microm or less, was orders of magnitude slower than those of previous reports. The release results indicate that the service life of our coatings could be far extended even with a small amount of zosteric acid incorporated.

All-optical control of light on a silicon chip.

Photonic circuits, in which beams of light redirect the flow of other beams of light, are a long-standing goal for developing highly integrated optical communication components. Furthermore, it is highly desirable to use silicon--the dominant material in the microelectronic industry--as the platform for such circuits. Photonic structures that bend, split, couple and filter light have recently been demonstrated in silicon, but the flow of light in these structures is predetermined and cannot be readily modulated during operation. All-optical switches and modulators have been demonstrated with III-V compound semiconductors, but achieving the same in silicon is challenging owing to its relatively weak nonlinear optical properties. Indeed, all-optical switching in silicon has only been achieved by using extremely high powers in large or non-planar structures, where the modulated light is propagating out-of-plane. Such high powers, large dimensions and non-planar geometries are inappropriate for effective on-chip integration. Here we present the experimental demonstration of fast all-optical switching on silicon using highly light-confining structures to enhance the sensitivity of light to small changes in refractive index. The transmission of the structure can be modulated by up to 94% in less than 500 ps using light pulses with energies as low as 25 pJ. These results confirm the recent theoretical prediction of efficient optical switching in silicon using resonant structures.

Guiding and confining light in void nanostructure.

We present a novel waveguide geometry for enhancing and confining light in a nanometer-wide low-index material. Light enhancement and confinement is caused by large discontinuity of the electric field at high-index-contrast interfaces. We show that by use of such a structure the field can be confined in a 50-nm-wide low-index region with a normalized intensity of 20 microm(-2). This intensity is approximately 20 times higher than what can be achieved in SiO2 with conventional rectangular waveguides.

All-optical switching on a silicon chip.

We present an experimental demonstration of fast all-optical switching on a silicon photonic integrated device by employing a strong light-confinement structure to enhance sensitivity to small changes in the refractive index. By use of a control light pulse with energy as low as 40 pJ, the optical transmission of the structure is modulated by more than 97% with a time response of 450 ps.

Mercurio en el cabello de embarazadas y madres lactantes chilenas / Mercury in the hair of pregnant and lactating Chilean women

Las aguas costeras de la Octava Región de Chile recibieron durante aproximadamente dos décadas desechos de mercurio de origen industrial. El objetivo del presente estudio, efectuado de 1991 a 1993, fue medir las concentraciones de mercurio en el cabello de mujeres embarazadas o lactantes de aldeas del litoral y del interior de esa región para examinar la relación entre la concentración de mercurio y el consumo de productos de mar, determinado por encuesta. En el cuestionario de encuesta usado en 1991 no se investigó la frecuencia del consumo de pescados, mariscos y algas y solo se tomaron en cuenta embarazadas y madres lactantes con un consumo mínimo semanal de una comida a base de pescado. En el cuestionario aplicado en 1992 y 1993 se investigó el consumo diario y semanal de productos marinos en general (pescado, mariscos o algas marinas). Mediante espectrofotometría se determinó la concentración de mercurio total en muestras de 100 mg de cabello de 153 mujeres embarazadas y lactantes de 11 aldeas de la Octava Región donde se consumían productos marinos con regularidad. Ninguna de las mujeres tenía exposición ocupacional al mercurio. También se determinó la concentración de mercurio total en muestras similares de cabello de mujeres de un grupo testigo compuesto de 26 embarazadas y lactantes de Pinto y el Carmen, aldeas en el interior de la misma región donde muy raras veces se comen productos de mar. La medida aritmética de las concentraciones capilares de mercurio total fue de 1,81 mg/kg de peso corporal para el grupo de estudio (con una desviación estándar (DE) de 1,52) y de 0,42 mg/kg para el grupo del interior (con una DE de 0,15), diferencia estadísticamente significativa (P0,01). También se observo una diferencia estadísticamente significativa (P0,05) entre la media del grupo del interior y la de las nueve aldeas más cercanas a las fuentes de contaminación, pero no entre aquella y la de las mujeres de las dos aldeas en los extremos norte y sur de la zona de estudio, que estaban más lejos de las aguas contaminadas. La concentración capilar de mercurio total fue significativamente mayor en las mujeres que indicaron comer pescado siete veces a la semana o más; en las que indicaron comer pescado, mariscos o algas cinco veces a la semana o más, y en las que habían vivido 20 años o más en su aldea. No se encontro ninguna diferencia estadísticamente significativa cuando los resultados se analizaron por edad

Mercurio en el cabello de embarazadas y madres lactantes chilenas / Mercury in the hair of pregnant and lactating Chilean women

Las aguas costeras de la Octava Región de Chile recibieron durante aproximadamente dos décadas desechos de mercurio de origen industrial. El objetivo del presente estudio, efectuado de 1991 a 1993, fue medir las concentraciones de mercurio en el cabello de mujeres embarazadas o lactantes de aldeas del litoral y del interior de esa región para examinar la relación entre la concentración de mercurio y el consumo de productos de mar, determinado por encuesta. En el cuestionario de encuesta usado en 1991 no se investigó la frecuencia del consumo de pescados, mariscos y algas y solo se tomaron en cuenta embarazadas y madres lactantes con un consumo mínimo semanal de una comida a base de pescado. En el cuestionario aplicado en 1992 y 1993 se investigó el consumo diario y semanal de productos marinos en general (pescado, mariscos o algas marinas). Mediante espectrofotometría se determinó la concentración de mercurio total en muestras de 100 mg de cabello de 153 mujeres embarazadas y lactantes de 11 aldeas de la Octava Región donde se consumían productos marinos con regularidad. Ninguna de las mujeres tenía exposición ocupacional al mercurio. También se determinó la concentración de mercurio total en muestras similares de cabello de mujeres de un grupo testigo compuesto de 26 embarazadas y lactantes de Pinto y el Carmen, aldeas en el interior de la misma región donde muy raras veces se comen productos de mar. La medida aritmética de las concentraciones capilares de mercurio total fue de 1,81 mg/kg de peso corporal para el grupo de estudio (con una desviación estándar (DE) de 1,52) y de 0,42 mg/kg para el grupo del interior (con una DE de 0,15), diferencia estadísticamente significativa (P0,01). También se observo una diferencia estadísticamente significativa (P0,05) entre la media del grupo del interior y la de las nueve aldeas más cercanas a las fuentes de contaminación, pero no entre aquella y la de las mujeres de las dos aldeas en los extremos norte y sur de la zona de estudio, que estaban más lejos de las aguas contaminadas. La concentración capilar de mercurio total fue significativamente mayor en las mujeres que indicaron comer pescado siete veces a la semana o más; en las que indicaron comer pescado, mariscos o algas cinco veces a la semana o más, y en las que habían vivido 20 años o más en su aldea. No se encontro ninguna diferencia estadísticamente significativa cuando los resultados se analizaron por edad